Intraluminal stents are commonly employed for treatment of various vascular conditions such as arteriosclerosis, often as coronary artery implants. A stent can be implanted at the site of a vessel stricture or steno sis using a conventional balloon catheter delivery system as used in angioplasty. Stents also maybe employed in body passageways other than blood vessels to treat strictures or prevent luminal occlusion. Such stents ordinarily consist of a cylindrical network of very small metal wires. The stent is inserted in a small-diameter configuration and then expanded to a large-diameter final configuration against the walls of the blood vessel or other body lumen. Such stent structures and implantation techniques are well known.
Great efforts have been expended to modify metallic stents to eliminate stress-induced and/or inflammation-induced restenosis, and to effectively deliver therapeutic agents to lesion sites. Some advancements in drug-coated metal stents have been made recently. However, metallic stents still present a potential vessel injury problem. Furthermore, the delivery of medicine to a lesion site either by local or systemic means is unsatisfactory with current stent and catheter technology. The present invention addresses these problems.